Although flood losses are difficult to assess in Queensland, as floodwaters have not fully receded and more rain is forecast, several deaths have occurred in that state, and tens of thousands of cattle are expected to perish. Urban warnings have been issued for snakes and crocodiles, more than three hundred cases of dengue have been reported in one town alone, and some communities may be isolated by floodwaters for as long as eight weeks. Some A$500,000 in Queensland produce spoiled and had to be destroyed when flooded highways prevented trucks from reaching food distribution depots.

Australians have taken to calling the current protracted drought “The Big Dry”. Heavy annual precipitation in the North is traditionally referred to as “The Big Wet.”

Southern Cities See Record Temperatures, Little Water

Minimum and maximum temperatures for Adelaide and Melbourne between 25 January and 1 February, 2009. Temperatures in Melbourne were driven even higher by the second heatwave on the following weekend. Click to enlarge.

Late January—already a historically dry month for the south of Australia—brought heat waves to the southern states that were unprecedented in both temperature and duration, with daily highs of more than 40 ºC (104 ºF) in Melbourne for three days in a row, peaking at 45.1 ºC (113.2 ºF) on 30 January. Buckled train tracks and sagging power lines interrupted much of the city’s passenger train service, and residents were advised to conserve water.

Although Victoria Premier John Brumby had expressed confidence in the resilience of the city’s power systems, blackouts affected as many as half a million of the city’s residents at a time. Telephone and internet services for hundreds of thousands of people were interrupted when primary, secondary, and redundant power systems failed. Record heat returned within a week, reaching 46.4 ºC (115.5 ºF) in the city on 7 February, the highest temperature recorded in Melbourne since measurements began 154 years ago.

In South Australia, Adelaide suffered five consecutive days with temperatures above 40 ºC, peaking at 45.7 ºC (114.3 ºF) on 28 January. Some parts of South Australia saw night temperatures above 41 ºC (106 ºF) before sunrise, an event that “appears to be without known precedent”, according to Australia’s Bureau of Meteorology (BOM).

The January-February 2009 event also produced seven of the eight highest temperatures on record for the island of Tasmania, off the coast of Victoria. Temperatures at eight island sites reached or surpassed 40 °C (104 ºF), a mark which had previously been reached just sixteen times in the state’s recorded history, and only in the southeast. All eight sites that saw temperatures at or above 40 ºC this year are in the state’s northern half.

The heat waves added to existing urban water stress; Melbourne’s water supply, for example, was at a 25-year low, with reservoirs two-thirds empty prior to the heat waves, and both Melbourne and Adelaide were already operating under Stage 3 water restrictions. Victoria’s current “Target 155” water conservation program recommends a household water usage goal of no more than 155 liters (41 gallons US) of water use per person per day.

During the heat waves, however, Melbourne’s average personal daily water consumption averaged as much as 240 liters (63 gallons US) per person per day, or about 55% above target. As of 12 February, a new bushfire threatened the Yarra Valley’s Thompson Reservoir, which supplies water to the city, as well as the Longford oil and natural gas plant. Warmer weather and lightning strikes are expected in the area next week.

Australia’s cities often employ flexible water conservation goals, depending on water catchment levels that support a given city; for example, South East Queensland employed a “Target 140” campaign in 2007, when a water crisis coincided with a need to upgrade existing infrastructure. By comparison, per capita personal daily water use in the United States, excluding industry, can be as high as 400 to 600 liters (106 to 159 gallons US) per day.

As the cities sweltered, a leaked government report revealed that water flows to Australia’s Snowy River had been diverted to the Murray River by the state of New South Wales to produce power and irrigate crops, despite promises to restore the Snowy River’s natural flows beginning in 2000. Current flows are 4% of normal and 30% below agreed restoration levels. ^[1]

“Hell In All Its Fury Has Visited Victoria”

Satellite image of Victoria bushfires burning, 9 February 2009. Source: NASA. Click to enlarge.

Most of Victoria’s worst bushfires started 7 February, with fire fronts that Australian Prime Minister Kevin Rudd termed “hell in all its fury”, reaching as high as 35 meters (115 feet) in some areas. A University of Melbourne senior lecturer in fire ecology, Kevin Tolhurst, calculated that radiant heat from the fires would be enough to kill at distances of up to 140 meters (460 feet), with conditions similar to Dresden firestorms rapidly increasing body core temperatures and interrupting metabolic processes. Bushfires can produce their own volatile gases and oils, adding fuel to the fire.

Australia’s Bureau of Meteorology uses a Forest Fire Danger Index (FFDI) that calculates the combined effects of near-surface maximum temperature, total precipitation, relative humidity, and wind speed for a given day to determine the intensity of a blaze. A rating of 100 indicates that a fire is uncontrollable. On 7 February, the FFDI reached 400.

We’ve never seen a day like that. We have had the driest air recorded, and it was three degrees hotter than [1983’s] Ash Wednesday.

—David Jones, head of the BOM’s National Climate Centre

Much of Victoria’s rainfall has been below average for the past twelve years, and Australia has recorded a warmer than average year for the past seven years.

Impacts of Queensland Floods “Beyond Human Intervention”

Tropical cyclones Charlotte and Ellie brought heavy precipitation that stalled over Queensland rather than moving on, triggering flood warnings for the Barcoo, Burdekin, Diamantina, Georgina, Herbert, Landsborough, Murray, Thomson, and Tully rivers, Eyre Creek, and the Gulf Rivers, including the Nicholson, Flinders, Glibert, and Norman river systems.

Thousands of head of cattle were stranded across vast areas of open land by surrounding floodwaters, and emergency fodder drops were considered but ultimately deemed impractical because of the scale of the event. Queensland Cattle Council president Greg Barns judged that the floods would devastate the state’s beef industry, remarking that “the situation in many cases is really beyond human intervention.”^[2] Queensland was hit hard by a 2007 deluge which was termed at the time a “one in a hundred years” event.

Role Of Climate Uncertain; Indian Ocean Dipole Remains Positive Three Years In A Row

Although scientists were careful to point out that no single heat or flood event can be conclusively tied to climate change, they warned that events such as the fires and floods of 2009 are consistent with climate models produced in the past, and are likely to be more common in the future.

In 2007, for example, the Intergovernmental Panel on Climate Change (IPCC) expressed “high confidence”—a 90% or greater likelihood—that climate change would bring greater risks to major infrastructure in Australia, with “design criteria for extreme events...very likely to be exceeded more frequently” by 2030, including more frequent heatwaves and flooding, as well as increased storm and fire damage and subsequent loss of life.^[3] A report by Australia’s own Commonwealth Scientific and Research Organization (CSIRO) in the same year found that “substantial increase in fire weather risk” likely at most sites in south-eastern Australia.^[4]

One potential threat multiplier for drought and bushfires is the Indian Ocean Dipole (IOD), a weather phenomenon that involves the oscillation of warmer and cooler sea surface temperatures (SST) between the eastern and western Indian Ocean. Although the IOD was identified in 1999^[5], fossil studies indicate that it has existed for at least 6,500 years.

Negative and positive phases of Indian Ocean Dipole (IOD), with subsequent effects on Australia. Source: University of New South Wales. Click to enlarge.

The positive pole, or phase, of the IOD brings cooler and drier conditions to the eastern Indian Ocean as winds weaken, drying out southeast Australia and parts of Indonesia. At the same time, warming seas and increased precipitation occur in the western Indian Ocean, affecting monsoons in India and eastern Africa. The negative phase of the IOD flips these conditions, generating winds that pick up moisture from the western Indian Ocean, which then sweeps down towards southern Australia to deliver precipitation.

A team of scientists led by Caroline Ummenhofer and Matthew England of the University of New South Wales Climate Change Research Centre has concluded that the Indian Ocean Dipole is the key driver of moisture-bearing winds that are carried across the southern half of Australia.^[6] The team was able to establish direct links between the IOD and all of Australia’s major droughts since 1885. A report of their findings has been submitted to Geophysical Research Letters.

Although the IOD normally oscillates between positive, negative, and neutral, it has been limited to positive and neutral phases since 1992, and has remained in a positive phase for the last three years. No such occurrence can be found in previous records of sea surface temperatures. Climatologists will not know for several months whether or not the IOD will remain in a positive phase for 2009.

Firefighters Call For Halving Of Greenhouse Gases by 2020

In an open letter posted in Australia’s The Age newspaper^[7][7], the United Firefighters’ Union of Australia appealed to Prime Minister Rudd and Victoria Premier John Brumby to move quickly on climate change. Research by CSIRO, the National Climate Institute, and the Bushfire Council projects that a low global warming scenario could see catastrophic fire events in parts of regional Victoria every five to seven years by 2020, increasing to every three to four years by 2050, with up to 50 per cent more extreme danger fire days.

Firefighters know that it is better to prevent an emergency than to have to rescue people from it, and we urge state and federal governments to follow scientific advice and keep firefighters and the community safe by halving the country’s greenhouse gas emissions by 2020.

—Peter Marshall, National Secretary, United Firefighters’ Union of Australia

A “high global warming scenario”, however, could trigger catastrophic events as often as once a year in Mildura by 2050, extreme danger fire days in Bendigo and Canberra could double, with catastrophic events predicted as often as every eight years.

Given the Federal Government’s dismal greenhouse gas emissions cut of 5 per cent, the science suggests we are well on the way to guaranteeing that somewhere in the country there will be an almost annual repeat of the recent disaster and more frequent extreme weather events.

—Peter Marshall

Early estimates of losses from both disasters topped A$2 billion (US$1.4 billion). Late last year, re-insurer Munich Re reported that 2008 was the third worst year on record for insured losses, with nine of the ten largest natural catastrophes of the year related to weather. (Earlier post.)

A poll carried out by Accenture and released today found that eight out of ten (84%) consumers in Australia say that they are concerned by climate change and believe it will directly impact their life (81%). 60% of Australians were found to be quite or very optimistic that humans will be able to take the necessary actions in order to solve global climate change.

However, a 2007 poll found that 88% of people contacted in Australia said they would be willing to switch to energy companies offering low carbon emission products and services, yet a year later, only 17% had switched gas or electricity provider, and just 5% had changed their oil provider.

^[1] Rick Wallace: NSW stealing Snowy’s precious flows. In The Australian, 6 February 2009
^[2] Padraic Murphy, The Queensland floods will devastate the beef industry as livestock starve. In The Australian, 6 February 2009
^[3] Kevin Hennessey et al.: IPCC Fourth Assessment Report, Working Group II: Australia and New Zealand. Cambridge University Press, 2007
^[4] CSIRO: Climate Change in Australia - Technical Report 2007.
^[5] N.H. Saji et al.: A dipole mode in the tropical Indian Ocean. In Nature, Volume 401, Issue 6751, 23 September 1999
^[6] Bob Beale, University of New South Wales: Indian Ocean causes Big Dry: drought mystery solved. 5 February 2009
^[7] Peter Marshall, Face global warming or lives will be at risk. In The Age, 12 February 2009